Medicinal preparations of the types mentioned are namely stored in special receptacles and at a defined temperature and must be defrosted within a certain time and/or heated to a prescribed temperature. Thus, for example, stem cell preparations which are recovered from bone marrow or blood, which are stored in a plastic bag with a capacity of 60 to 110 ml in liquid nitrogen at −196° C. should be completely thawed within 3 to 6 minutes. The final temperature of such a preparation should not exceed a value of 10° C. since otherwise the survival rate of the life-containing cells is drastically reduced. In addition, it must be ensured that the storage conditions of the stem cells are optimum hygienic conditions so that in the case of a leakage of the vessel, a contamination of the stem cell preparation can be excluded.
Usually the aforementioned medicinal products, especially stem cell preparations, are defrosted or heated with the aid of open water baths which are temperature controlled at 37 to 42° C. The stem cell preparation is then immersed by hand in the water bath and moved in the water. By visual inspection it is possible to determine when the defrosting process has been concluded and the bag should be withdrawn from the water. Since in this case there is a direct contact between water and the plastic bag, a contamination of the stem cell preparation cannot be excluded.
In addition, it can happen that the conclusion of the defrosting is recognized too late and the survival rate of the stem cells significantly reduced as a consequence of the temperature of the product.
To improve this situation, there is proposed in DE 37 20 41 051 a defrosting and temperature control device in conjunction with the defrosting of preserved plasma or preserved blood. With the known device, preserved plasma or preserved blood usually frozen at −18° C. is disposed between two plastic bags traversed by a temperature control medium, preferably water. The arrangement is subjected to a shaking movement via an eccentric so as to insure a uniform temperature distribution. The plastic bag is then, as a rule, temperature controlled to 37° C. The desired end temperature of the preserved plasma or preserved blood.
As a drawback, it has been found that while the temperature of the temperature control medium in such systems amounts to a constant 37° C. during the defrosting or heating, but the temperature of the product to be temperature controlled cannot be ascertained. If a heating in a water bath or with the aid of the known device is carried out, therefore, an overheating cannot be excluded and thus the risk that the stem cell preparation will become unusable is unusually high. A further disadvantage of the known system lies in the cleaning and sterilization. Thus in the case of the device of DE 37 41 051, the plastic bag and the rest of the device must be made germ free. The expense of this is very high since the temperature controlled cushions are fixedly connected with the temperature control device and are accessible only with difficulty. From the chemical loading of the temperature controlled cushions fabricated from plastic, through the use of disinfectants, from the thermal loads on the cushions through high differences between the starting and final temperatures of the temperature controlled product and through mechanical loads on the cushions through movement of the cushions as a consequence of the handling of the system, it is not possible to avoid the development of leaks with time. The result is a significant impairment of the hygiene in the environment of the stem cell, if, during the defrosting of a stem cell preparation in the device of DE 37 41 051, the stem cell preparation should runoff as a consequence of the failure of the seal of the storage receptacle.